self.jumpTo({‘x’: 76, ‘y’: 51}) works fine for me.
‘undefined is not a function’ would indicate that you do not have self.jumpTo() available, are you sure you have the Boots of Jumping or Boots of Leaping equiped?
Also, note that like move, jumpTo must be in a loop to work correctly. Otherwise it will not jump the full distance.
I am not aware of any property which returns the jump distance, if there is one it’s not documented. But i’ve observed that the Boots of Leaping have a jump distance of 18.